"The Speaker’s got tough calls to make on the fly."

The Speaker of the House of Commons shut down the NDP's ethics critic Thursday with a strict enforcement of rules against props that appeared to confuse some members of Parliament.

But Nathan Cullen says he has no sore feelings towards House referee Geoff Regan.

"The Speaker's got tough calls to make on the fly and when the government benches are losing their minds on him, often times Speakers will err on the side of caution," Cullen told HuffPost Canada Thursday.

Cullen says it all came down to a green piece of paper he inadvertently held up in question period — which had the word "RESPECT" on it — and Liberal "sensitivity" about his barbs for Finance Minister Bill Morneau.

The MP tried to take shine off Morneau's earlier announcement that he will donate to charity the profits earned on shares from his family business since he was elected in 2015. Cullen pushed the federal ethics commissioner to investigate Morneau for introducing pension reform legislation that could benefit Morneau Shepell, a pension management business.

The ethics watchdog later announced she will examine allegations that Morneau was in a conflict of interest when he introduced the bill.

'Oh, come on'

"Now that he's been caught profiting from a bill that he himself introduced he's trying to buy his way out of the problem," Cullen charged. "Maybe on Bay St. when someone commits a crime, they just ask the judge: how much do I have to make the cheque out for?

"But it doesn't work that way in the House of Commons. This is an admission of guilt by no other means."

Regan cut the MP off, citing his use of a prop, and Cullen lost the chance to finish his remarks.

"What prop?" one MP said.

"Oh, come on," said another.

"What are you talking about?"

'The Liberal benches didn't like my question'': Cullen

But Cullen told HuffPost he doesn't blame Regan for the decision and suggested it was actually the result of government MPs tattling on him.

"The Liberal benches didn't like my question," he said, chuckling. "So, on the thinnest of reasons jumped up to accuse me of doing something wrong to try to shut me down, to silence my question."

Still, Cullen said it was a "bit rich" coming from the Grit bench.

In question period last December, then-Democratic Institutions Minister Maryam Monsef held up a card displaying a math formula to mock months of work by the all-party committee on electoral reform.

Fred Chartrand/CP
Maryam Monsef Minister of Democratic Institutions stands in the House of Commons on Dec. 1, 2016.

Cullen told HuffPost the Speaker wasn't in a position to see that Monsef was holding up a card to make a point.

And last Wednesday, Prime Minister Justin Trudeau took out a copy of his party's 2015 platform to remind everyone about Liberal promises to cut the small business tax rate. Regan did not call out Trudeau for using a prop.

Sean Kilpatrick/CP
Prime Minister Justin Trudeau reads from his party's 2015 platform in the House of Commons on Oct. 18, 2017.

Heather Bradley, director of communications for the Speaker's office, told HuffPost in an email that Trudeau pulling out the platform was within the rules because members are permitted to read from "notes."

Cullen said Monsef and Trudeau "looked silly" in both cases but New Democrats weren't going to "cry like babies" about it.

"If the Liberals want to moan about that kind of stuff, let them," he said. "But they can't be hypocrites on it, which they are."